Biological
evolution was originally understood as a gradual, internally-driven process,
and standing biodiversity entirely the result of the slow accumulation of
positive changes. It is now clear that macroevolution (above species level)
proceeds in booms and busts. It is influenced by emergent multiscale processes,
which can turn short-term positive traits into long-term negatives and alter
rates of evolutionary change. Because these processes play out over thousands
to millions of years, they cannot be observed on generational timescales.
Fortunately, the fossil record preserves this evolutionary history, documenting
the responses of lineages to myriad conditions global and local. Here. I show
the potential of this database of natural experiments, using examples in which
I applied novel approaches from disparate fields to the vertebrate fossil
record of the Devonian-Mississippian (419-323 million years ago). This critical
interval in vertebrate evolution contained both repeated rounds of
diversification under varied conditions and a major climate-driven mass extinction
event. These investigations have already revealed new and surprising
information on the rise of modern fishes and faunas, the evolutionary outcomes
of gradual and sudden climate change, the drivers of adaptive radiation, the
origins of “living fossils,” and the role of macroecology in shaping evolution.
Many of these results have overturned previous hypotheses, opening new paths of
inquiry. Devonian-Carboniferous patterns and processes were likely repeated
under similar conditions throughout evolutionary history, and might represent
generalities in biological macroevolution.